214 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



bly bad, therefore, reached a stage of deterioration, when they were 

 eaten by the ancient inhabitants of the regions of the Little Belt. 



If the European oyster could live in the present water of the Baltic, 

 it would not have set the limit of its domain near the island of Anhalt, 

 in the Kattegat. That the oysters have been driven from the Baltic 

 by its waters gradually losing their saltness, may be seen from the fact 

 that on the eastern, the Swedish coast of the Baltic, where the water is 

 less salty than in the middle and the western (Jutland) coasts of the 

 Kattegat, they have retired farthest towards the Skagerack. 



The most recent attempt to cultivate oysters in the Baltic is princi- 

 pally distinguished from the former failures by the fact that it has been 

 made, not with our European species, which, as experience has shown, 

 cannot live in the Baltic, but with another kind, the North American 

 oyster, Ostrea virginiana Lester. 



The North American oyster is longer than the European in the direc- 

 tion from the ligament toward the edge of the stomach. In the same 

 direction the impressions of the adductors is, when compared with its 

 breadth, of larger extent, and its fore part is blunter than in our Ostrea 

 edulis, and has a more or less of a dark, violet color. The indentation 

 in the left or hollow valve is narrower and deeper than with our oyster; 

 nor does it have the low, wart-shaped teeth, which in the Ostrea edulis 

 are found on the anterior and posterior edges below the ligament. The 

 Ostrea virginiana grows to the length of one foot (more than 30 centi- 

 meters). Like Ostrea edulis, it spawns during the warm months. On 

 the coast of Virginia aud Maryland, on shallow beds which are more ex- 

 posed to the rays of the sun, they spawn as early as May, according to 

 W. K. Brooks, and on beds at a depth of 9-11 meters in July. Brooks 

 estimates the number of eggs of a full-grown American oyster at nine 

 millions.* As the eggs do not develop in the beard of the mother oys- 

 ter, and are therefore not protected by her, as is the case with the em- 

 bryos of the European oyster, the American oyster needs a greater 

 fecundity than the European, if it is to increase in spite of the manifold 

 destruction of the eggs and young. 



The idea of cultivating North American oysters in the Little Belt 

 was conceived by the late engineer, Mr. C. C. P. Meyer, of Hadersle- 

 ben, who had spent some time in America. When Meyer came to Kiel 

 to communicate to me his plan and ask my advice, I advised him to 

 place oysters on the east coast of Schleswig only in such locations where 

 they could not be covered with mud and sand or by masses of living or 

 dead plants; lor the American, like the European, oyster, after it has 

 once adhered to some portion of the bottom of the sea, can no longer move 

 about, and must perish if it is covered with mud, sand, or plants. 



Meyer found some persons to join him in his enterprise. A company 

 was formed which obtained permission from the provincial govern- 



• W. K. Brooks: Development of the American oyster (Ostrea virginiana), in report 

 of the Commission of Fisheries of Maryland for 1880. Baltimore, 1880. 



